[syzbot] [ext4?] kernel BUG in ext4_ext_insert_extent (2)

[syzbot] [ext4?] kernel BUG in ext4_ext_insert_extent (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    0af2f6be1b42 Linux 6.15-rc1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17198c04580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f175b153b655dbb3
dashboard link: https://syzkaller.appspot.com/bug?extid=ad86dcdffd6785f56e03
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f1d71d1bf77d/disk-0af2f6be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7f1638f065da/vmlinux-0af2f6be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9b3e49834705/bzImage-0af2f6be.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad86dcdffd6785f56e03@syzkaller.appspotmail.com

EXT4-fs error (device loop3): mb_free_blocks:1945: group 0, inode 19: block 289:freeing already freed block (bit 18); block bitmap corrupt.
------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:2151!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 6611 Comm: syz.3.178 Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:ext4_ext_insert_extent+0x317c/0x4610 fs/ext4/extents.c:2151
Code: 8b 74 24 60 e8 c5 ab ff ff 48 89 04 24 e9 2c da ff ff e8 97 40 4c ff 41 8d 9c 1c 00 80 ff ff e9 be ee ff ff e8 85 40 4c ff 90 <0f> 0b e8 7d 40 4c ff 44 01 e3 e9 1f f1 ff ff e8 70 40 4c ff 01 dd
RSP: 0018:ffffc900049ff0f0 EFLAGS: 00010287
RAX: 000000000004b428 RBX: ffff88807e54ec30 RCX: ffffc9000c50b000
RDX: 0000000000080000 RSI: ffffffff826efc8b RDI: 0000000000000004
RBP: ffff88804d74c418 R08: 0000000000000004 R09: 0000000000000028
R10: 0000000000000028 R11: 0000000000000000 R12: 0000000000000028
R13: 0000000000000028 R14: 0000000000000054 R15: ffff888053f4dc18
FS:  00007fe2885d66c0(0000) GS:ffff8881249b9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3080cff8 CR3: 000000005ea0a000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_ext_map_blocks+0x205b/0x5d60 fs/ext4/extents.c:4400
 ext4_map_create_blocks fs/ext4/inode.c:519 [inline]
 ext4_map_blocks+0x45b/0x1390 fs/ext4/inode.c:705
 _ext4_get_block+0x24e/0x5a0 fs/ext4/inode.c:784
 ext4_get_block_unwritten+0x29/0x110 fs/ext4/inode.c:817
 ext4_block_write_begin+0x3fb/0xf40 fs/ext4/inode.c:1066
 ext4_write_begin+0x670/0x11f0 fs/ext4/inode.c:1221
 ext4_da_write_begin+0x29d/0x990 fs/ext4/inode.c:2931
 generic_perform_write+0x3d0/0x930 mm/filemap.c:4102
 ext4_buffered_write_iter+0x119/0x440 fs/ext4/file.c:299
 ext4_file_write_iter+0xa4c/0x1d10 fs/ext4/file.c:718
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x5bd/0x1180 fs/read_write.c:684
 ksys_write+0x12a/0x240 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe28778d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe2885d6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe2879a5fa0 RCX: 00007fe28778d169
RDX: 000000000000fcb8 RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007fe28780e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe2879a5fa0 R15: 00007ffee8100088
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_insert_extent+0x317c/0x4610 fs/ext4/extents.c:2151
Code: 8b 74 24 60 e8 c5 ab ff ff 48 89 04 24 e9 2c da ff ff e8 97 40 4c ff 41 8d 9c 1c 00 80 ff ff e9 be ee ff ff e8 85 40 4c ff 90 <0f> 0b e8 7d 40 4c ff 44 01 e3 e9 1f f1 ff ff e8 70 40 4c ff 01 dd
RSP: 0018:ffffc900049ff0f0 EFLAGS: 00010287
RAX: 000000000004b428 RBX: ffff88807e54ec30 RCX: ffffc9000c50b000
RDX: 0000000000080000 RSI: ffffffff826efc8b RDI: 0000000000000004
RBP: ffff88804d74c418 R08: 0000000000000004 R09: 0000000000000028
R10: 0000000000000028 R11: 0000000000000000 R12: 0000000000000028
R13: 0000000000000028 R14: 0000000000000054 R15: ffff888053f4dc18
FS:  00007fe2885d66c0(0000) GS:ffff8881249b9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb70b406378 CR3: 000000005ea0a000 CR4: 0000000000350ef0


---
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [ext4?] kernel BUG in ext4_ext_insert_extent (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    739a6c93cc75 Merge tag 'nfsd-6.16-1' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15a19b0c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d11f52d3049c3790
dashboard link: https://syzkaller.appspot.com/bug?extid=ad86dcdffd6785f56e03
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14af2182580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f5a65b9fc0ed/disk-739a6c93.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3f1b70f2f048/vmlinux-739a6c93.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8ab27807c85/bzImage-739a6c93.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/376364fe7b8f/mount_2.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=10af2182580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad86dcdffd6785f56e03@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:2153!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 6732 Comm: syz.4.53 Not tainted 6.16.0-rc2-syzkaller-00318-g739a6c93cc75 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:ext4_ext_insert_extent+0x4ab7/0x4af0 fs/ext4/extents.c:2153
Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c a6 e7 ff ff 48 89 df e8 2c 8b b6 ff e9 99 e7 ff ff e8 62 0d 53 ff 90 0f 0b e8 5a 0d 53 ff 90 <0f> 0b e8 52 0d 53 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c
RSP: 0018:ffffc9000455ec60 EFLAGS: 00010293
RAX: ffffffff826d4f26 RBX: 0000000000000023 RCX: ffff888026e93c00
RDX: 0000000000000000 RSI: 0000000000000023 RDI: 0000000000000023
RBP: ffffc9000455ee10 R08: ffff8880609943a7 R09: 1ffff1100c132874
R10: dffffc0000000000 R11: ffffed100c132875 R12: 0000000000000023
R13: dffffc0000000000 R14: ffff88806bfde448 R15: ffff888027bf3d00
FS:  00007fe4a5ed66c0(0000) GS:ffff888125d51000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000003000 CR3: 0000000070c0d000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_ext_map_blocks+0x1792/0x6ac0 fs/ext4/extents.c:4404
 ext4_map_create_blocks fs/ext4/inode.c:609 [inline]
 ext4_map_blocks+0x931/0x18d0 fs/ext4/inode.c:813
 _ext4_get_block+0x200/0x4c0 fs/ext4/inode.c:892
 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:925
 ext4_block_write_begin+0x6f8/0x14b0 fs/ext4/inode.c:1178
 ext4_write_begin+0xa4f/0x1680 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x449/0xd20 fs/ext4/inode.c:3057
 generic_perform_write+0x2c7/0x910 mm/filemap.c:4112
 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299
 ext4_file_write_iter+0x298/0x1bc0 fs/ext4/file.c:-1
 do_iter_readv_writev+0x56e/0x7f0 fs/read_write.c:-1
 vfs_writev+0x31a/0x960 fs/read_write.c:1057
 do_pwritev fs/read_write.c:1153 [inline]
 __do_sys_pwritev2 fs/read_write.c:1211 [inline]
 __se_sys_pwritev2+0x179/0x290 fs/read_write.c:1202
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe4a4f8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe4a5ed6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007fe4a51b5fa0 RCX: 00007fe4a4f8e929
RDX: 0000000000000001 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007fe4a5010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000005412 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe4a51b5fa0 R15: 00007fffc4eaed48
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_insert_extent+0x4ab7/0x4af0 fs/ext4/extents.c:2153
Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c a6 e7 ff ff 48 89 df e8 2c 8b b6 ff e9 99 e7 ff ff e8 62 0d 53 ff 90 0f 0b e8 5a 0d 53 ff 90 <0f> 0b e8 52 0d 53 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c
RSP: 0018:ffffc9000455ec60 EFLAGS: 00010293
RAX: ffffffff826d4f26 RBX: 0000000000000023 RCX: ffff888026e93c00
RDX: 0000000000000000 RSI: 0000000000000023 RDI: 0000000000000023
RBP: ffffc9000455ee10 R08: ffff8880609943a7 R09: 1ffff1100c132874
R10: dffffc0000000000 R11: ffffed100c132875 R12: 0000000000000023
R13: dffffc0000000000 R14: ffff88806bfde448 R15: ffff888027bf3d00
FS:  00007fe4a5ed66c0(0000) GS:ffff888125d51000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005610a8772950 CR3: 0000000070c0d000 CR4: 0000000000350ef0


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] [ext4?] kernel BUG in ext4_ext_insert_extent (2)

[syzbot]

syzbot has bisected this issue to:

commit 665575cff098b696995ddaddf4646a4099941f5e
Author: Dave Hansen <dave.hansen@linux.intel.com>
Date:   Fri Feb 28 20:37:22 2025 +0000

    filemap: move prefaulting out of hot write path

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1434a3d4580000
start commit:   739a6c93cc75 Merge tag 'nfsd-6.16-1' of git://git.kernel.o..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1634a3d4580000
console output: https://syzkaller.appspot.com/x/log.txt?x=1234a3d4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d11f52d3049c3790
dashboard link: https://syzkaller.appspot.com/bug?extid=ad86dcdffd6785f56e03
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14fb2b0c580000

Reported-by: syzbot+ad86dcdffd6785f56e03@syzkaller.appspotmail.com
Fixes: 665575cff098 ("filemap: move prefaulting out of hot write path")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [ext4?] kernel BUG in ext4_ext_insert_extent (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    40f92e79b0aa Merge tag 'block-6.16-20250710' of git://git...
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14314d82580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bd2783a0a99d4ed0
dashboard link: https://syzkaller.appspot.com/bug?extid=ad86dcdffd6785f56e03
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11ce7a8c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=152fc68c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f33b9048bb66/disk-40f92e79.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1194a16e19e9/vmlinux-40f92e79.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bd82e554bd44/bzImage-40f92e79.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/ead6dd3b0e30/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=17a760f0580000)

The issue was bisected to:

commit 665575cff098b696995ddaddf4646a4099941f5e
Author: Dave Hansen <dave.hansen@linux.intel.com>
Date:   Fri Feb 28 20:37:22 2025 +0000

    filemap: move prefaulting out of hot write path

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1434a3d4580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1634a3d4580000
console output: https://syzkaller.appspot.com/x/log.txt?x=1234a3d4580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad86dcdffd6785f56e03@syzkaller.appspotmail.com
Fixes: 665575cff098 ("filemap: move prefaulting out of hot write path")

------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:2153!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 5856 Comm: syz-executor355 Not tainted 6.16.0-rc5-syzkaller-00193-g40f92e79b0aa #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:ext4_ext_insert_extent+0x4ab7/0x4af0 fs/ext4/extents.c:2153
Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c a6 e7 ff ff 48 89 df e8 3c 95 b6 ff e9 99 e7 ff ff e8 a2 3d 55 ff 90 0f 0b e8 9a 3d 55 ff 90 <0f> 0b e8 92 3d 55 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c
RSP: 0018:ffffc9000437ec60 EFLAGS: 00010293
RAX: ffffffff826af7b6 RBX: 000000000000001d RCX: ffff88802dd18000
RDX: 0000000000000000 RSI: 000000000000001d RDI: 000000000000001d
RBP: ffffc9000437ee10 R08: ffff8880738b3ae7 R09: 1ffff1100e71675c
R10: dffffc0000000000 R11: ffffed100e71675d R12: 000000000000001d
R13: dffffc0000000000 R14: ffff8880721f643c R15: ffff888027204700
FS:  00007fa4a23966c0(0000) GS:ffff888125d4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f42dc5c1000 CR3: 000000003299c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ext4_ext_map_blocks+0x1792/0x6ac0 fs/ext4/extents.c:4404
 ext4_map_create_blocks fs/ext4/inode.c:609 [inline]
 ext4_map_blocks+0x931/0x18d0 fs/ext4/inode.c:813
 _ext4_get_block+0x200/0x4c0 fs/ext4/inode.c:892
 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:925
 ext4_block_write_begin+0x6f8/0x14b0 fs/ext4/inode.c:1178
 ext4_write_begin+0xa4f/0x1680 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x449/0xd20 fs/ext4/inode.c:3057
 generic_perform_write+0x2c4/0x910 mm/filemap.c:4112
 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299
 ext4_dio_write_iter fs/ext4/file.c:613 [inline]
 ext4_file_write_iter+0x182a/0x1bc0 fs/ext4/file.c:721
 do_iter_readv_writev+0x56b/0x7f0 fs/read_write.c:-1
 vfs_writev+0x31a/0x960 fs/read_write.c:1057
 do_pwritev fs/read_write.c:1153 [inline]
 __do_sys_pwritev2 fs/read_write.c:1211 [inline]
 __se_sys_pwritev2+0x179/0x290 fs/read_write.c:1202
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa4a23e16f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa4a2396208 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007fa4a2468648 RCX: 00007fa4a23e16f9
RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000007
RBP: 00007fa4a2468640 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7b R11: 0000000000000246 R12: 00007fa4a2435620
R13: 0000200000000140 R14: 00002000000001c0 R15: 0000200000000080
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_insert_extent+0x4ab7/0x4af0 fs/ext4/extents.c:2153
Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c a6 e7 ff ff 48 89 df e8 3c 95 b6 ff e9 99 e7 ff ff e8 a2 3d 55 ff 90 0f 0b e8 9a 3d 55 ff 90 <0f> 0b e8 92 3d 55 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c
RSP: 0018:ffffc9000437ec60 EFLAGS: 00010293

RAX: ffffffff826af7b6 RBX: 000000000000001d RCX: ffff88802dd18000
RDX: 0000000000000000 RSI: 000000000000001d RDI: 000000000000001d
RBP: ffffc9000437ee10 R08: ffff8880738b3ae7 R09: 1ffff1100e71675c
R10: dffffc0000000000 R11: ffffed100e71675d R12: 000000000000001d
R13: dffffc0000000000 R14: ffff8880721f643c R15: ffff888027204700
FS:  00007fa4a23966c0(0000) GS:ffff888125d4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff12275000 CR3: 000000003299c000 CR4: 00000000003526f0


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.